University of California San Diego engineers have fabricated the first-ever semiconductor-free, optically-controlled microelectronic device. Their discovery paves the way for microelectronic devices that are faster and capable of handling more power, and could also lead to more efficient solar panels. Using metamaterials, the engineers built a microscale device that exhibits a 1,000 percent increase in conductivity when activated by low voltage and a low-power laser. The capabilities of existing microelectronic devices, such as transistors, are limited by the properties of their constituent materials, such as their semiconductors. Semiconductors can impose limits on a device’s conductivity, or electron flow. Semiconductors have a band gap and require a boost of external energy to get electrons to flow through them. Electron velocity is limited, since electrons are constantly colliding with atoms as they flow through the semiconductor.